<template>
  <!--既可以是驼峰写法，也跨域是-的写法-->
  <HomePanel title="热门品牌" sub-title="国际经典 品质保证">
    <template v-slot:right>
      <a @click="toggle(-1)" :class="{disabled:index===0}" href="javascript:;"
         class="iconfont icon-angle-left prev"></a>
      <a @click="toggle(1)" :class="{disabled:index===1}" href="javascript:;"
         class="iconfont icon-angle-right next"></a>
    </template>
    <div class="box" ref="target">
      <Transition>
        <ul v-if="brandList.length" class="list" :style="{transform:`transLateX(${-index*1240}px)`}">
          <li v-for="item in brandList" :key="item.id">
            <RouterLink to="/">
              <img :src="item.picture" alt="">
            </RouterLink>
          </li>
        </ul>
        <HomeSkeleton v-else/>
      </Transition>
    </div>
  </HomePanel>
</template>
<script>
import HomePanel from '@/views/home/components/home-panel'
import { ref } from 'vue'
import { findBrand } from '@/api/home'
import { useLazyData } from '@/hooks'
import HomeSkeleton from '@/views/home/components/home-skeleton'

export default {
  name: 'HomeBrand',
  components: {
    HomeSkeleton,
    HomePanel
  },
  setup () {
    // const brandList = ref([])
    // findBrand().then(data => {
    //   brandList.value = data.result
    // })
    // 懒加载方式
    // 注意useLazyData需要的参数是API函数（API），如果需要传参数给APi函数（API），自己写函数（A）作为参数，在函数（A）中调用API函数
    // 函数A:()=>{}  API函数：findBrand(10)
    const {
      target,
      result
    } = useLazyData(() => findBrand(10))

    // 切换效果，前提是只有两页
    // 1.点击上一页
    // 2.点击下一页
    const index = ref(0)
    const toggle = (step) => {
      const newIndex = index.value + step
      if (newIndex < 0 || newIndex > 1) {
        return
      }
      index.value = newIndex
    }
    return {
      brandList: result,
      target,
      index,
      toggle
    }
  }
}
</script>

<style scoped lang='less'>
.home-panel {
  background: #f5f5f5
}

.iconfont {
  width: 20px;
  height: 20px;
  background: #ccc;
  color: #fff;
  display: inline-block;
  text-align: center;
  margin-left: 5px;
  background: @xtxColor;

  &::before {
    font-size: 12px;
    position: relative;
    top: -2px
  }

  &.disabled {
    background: #ccc;
    cursor: not-allowed;
  }
}

.box {
  display: flex;
  width: 100%;
  height: 345px;
  overflow: hidden;
  padding-bottom: 40px;

  .list {
    width: 200%;
    display: flex;
    transition: all 1s;

    li {
      margin-right: 10px;
      width: 240px;

      &:nth-child(5n) {
        margin-right: 0;
      }

      img {
        width: 240px;
        height: 305px;
      }
    }
  }
}
</style>
